OTTAWA - A broad coalition of former diplomats and public servants is questioning whether Stephen Harper's return to the United Nations this week is politically motivated.

The World Federalist Movement renewed its criticism Wednesday that the prime minister has snubbed the UN and downgraded Canada's relations with the world's most influential multilateral body since taking power in 2006.

John Trent, a University of Ottawa expert on international political science, said Harper's return to the UN is welcome — but could well be motivated by the prospect of a coming federal election at home.

"Unfortunately, we have not been there for the last 10 years really, and now Mr. Harper's going down for the first time in four years to speak to the United Nations," Trent told a press conference on Parliament Hill.

"Does it mean that Canada is back and going to work at the United Nations or is this just an electoral ploy?"

Carolyn McAskie, a former top official at the now defunct Canadian International Development Agency, said Harper's foreign policy decisions are dictated by what diaspora groups he can court votes from within Canada.

"I have heard middle level senior civil servants, when asked how they make their policy decisions, talk about 'voter pockets,' McAskie said.

"I left the government in 1999 after 30 years in the government. I never heard a public servant talk about voter pockets."

Harper will address the UN General Assembly on Thursday, his third address since taking power, and first since Canada lost its bid for a temporary seat on the UN Security Council in 2010.

Harper was to address the Security Council on Wednesday at the request of the United States, which is seeking further international help in the fight against militants in Iraq and Syria.

Earlier this week, Harper made it clear he has a full schedule in New York, and is fully engaged on a number of top international security issues, including the fight against Islamic militants and pro-Russian separatists in Ukraine.

Harper is expected to devote a significant portion of his General Assembly address to his signature foreign aid priority: improving maternal, newborn child health in developing countries.

Earlier this year, Harper made a five-year, $3.5-billion commitment to 2020, and he said he would be seeking further contributions for other countries and business interests.